The present invention relates to a clutch unit interposed between the Input and output members for transmitting and interrupting torque in an opening and closing mechanism, such as an automobile power window. electrically-powered slide door (one-box car), electrically-powered curtain or the like.
For example, the electrically-powered slide door of an automobile is usually designed such that the rotative power of the driving motor is reduced in speed by a worm and wormwheel mechanism and then transmitted through a solenoid clutch to an output shaft for opening and closing the door. Reducing the speed of the driving motor by a worm and wormwheel mechanism requires the use of a small-sized motor because of the limited installation space and the high rpm and low torque at which the driving motor runs, as compared with the low rpm and high torque of the output shaft necessary for the output shaft to open and close the door. Further, the use of a solenoid clutch is intended to make it possible to open and close the door by manual power input from the output shaft, i.e., by manual operation. That is, since the gear reduction ratio of a worm and wormwheel mechanism is generally high, the connection between the driving motor and the output shaft has to be cancelled before manual opening and closing of the door during stoppage of the driving motor can be made possible.
However. Interposition of a solenoid clutch between the driving motor and the output shaft is liable to increase the power consumption and complicate the control system.